Abstract
The effect of the temperature of gas phase CO upon the kinetics of the oxygen titration reaction: COg +Oa → CO2,g, has been studied. It is found that the reaction's rate is independant of CO gas temperature between 300 and 623 K. The activation energy (6.5 kcal/mole), dependence upon CO pressure (first-order), and independence upon oxygen coverage for 0.1 ≤ θo ≤ 0.4 are all independant of the CO gas phase temperature. This result rules out any Eley-Rideal type mechanism whereby CO reacts directly from the gas phase with an oxygen adatom without first being accommodated to the surface temperature in an absorbed state. The result is instead interpretable in terms of a Langmuir-Hinshelwood mechanism.
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This can be calculated using the formula for the equilibrium θCO (eq 1) given in ref. [2]
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Camille and Henry Dreyfus Foundation Teacher-Scholar Fellowship.
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Domagala, M.E., Campbell, C.T. The mechanism of CO oxidation over Cu(110): Effect of CO gas energy. Catal Lett 9, 65–70 (1991). https://doi.org/10.1007/BF00769083
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DOI: https://doi.org/10.1007/BF00769083